Time-of-use Tariff Savings Calculator
Compare flat and time-of-use annual costs from your off-peak and peak usage and calculate a break-even off-peak share.
A QUICK WALKTHROUGH
How to use this tool
- Enter annual off-peak and peak kWh.
- Enter flat and time-of-use rates, daily fees and one currency.
- Calculate costs, signed flat−ToU savings and break-even share, then copy or download the report.
Formula and units
U=O+P. Flat=U×rf+365sf. ToU=O×ro+P×rp+365st. Savings=Flat−ToU. Break-even share=[U(rp−rf)+365(st−sf)]/[U(rp−ro)].
Scope
A365-day year and constant entered rates are assumed. The share calculation varies the usage split while keeping total usage fixed. Zero usage, equal peak/off-peak rates or a crossing outside0–100% need explicit interpretation. No supplier or switching recommendation is made.
Local processing
Inputs stay in your browser. The report includes inputs, formulas and scope.
GOOD TO KNOW
Common questions
What does a negative savings value mean?
It means the entered time-of-use cost is higher than the entered flat cost. It is only this arithmetic scenario.